1. Field of the Invention
This invention relates to a toner seal member for preventing leakage of fine powder, and a process cartridge detachably mountable to the main body of an image forming apparatus.
2. Related Background Art
Conventionally, in electrophotographic image forming apparatus, an image bearing member (hereinafter “photosensitive drum”) charged uniformly electrostatically by a charging means is selectively exposed to light to form an electrostatic latent image on the photosensitive drum surface. Then, a developer (toner) is fed from a developer carrying member developing sleeve to the photosensitive drum to make the latent image visible, and thereafter the toner image formed is transferred to a recording medium, and is further fixed by the action of heat and pressure.
Transfer residual toner not transferred and having remained on the photosensitive drum is scraped off the photosensitive drum by a cleaning means, and the transfer residual toner is collected in a waste toner holder by means of a scoop sheet which is provided upstream as seen from the direction of rotation of the photosensitive drum, without scattering inside the image forming apparatus main body.
Here, as the cleaning means, a method is widely used in which a cleaning blade made of an elastic material, such as rubber that is provided in contact with the photosensitive member surface, is attached to a cleaning frame member.
At both ends of the cleaning frame member, toner seal members are attached in order to prevent the toner from leaking through gaps between the cleaning blade and the cleaning frame member and between the photosensitive drum and the cleaning frame member.
Toner seal members are also attached on the side of a development frame member, corresponding to both lengthwise ends of the developing sleeve, and gaps between the developing sleeve and the development frame member are sealed to prevent the toner from scattering or leaking therethrough.
In conventional toner seal members, used are (a) a layered structure in which a high-density polyethylene is stuck to a part of an elastic member made of foamed polyurethane, (b) a layered structure in which an elastic member made of foamed polyurethane or wool or synthetic-fiber felt is bonded to a felt layer of fluorine fiber, and (c) a layered structure in which an elastic member made of foamed polyurethane or wool or synthetic-fiber felt is bonded to a pile fabric of fluorine fiber (see, e.g., Japanese Patent Application Laid-Open No. 2001-290405.).